Thin and lightweight electronic products have become a major development trend in the increasing demand of mobile devices. As electronic components have their size reduced, more efficient heat dissipation is required, especially for components such as the chip, the backlight module and the battery. Synthetic flexible graphite films can meet the high requirements of thermal conduction (its thermal conductivity is four times better than that of copper) and heat dissipation, and offer good flexibility. Accordingly, graphite films are widely used in the manufacture of mobile devices.
A graphite film having high thermal conductivity can be fabricated by performing multiple processing steps of pyrolysis and atom rearrangement to produced pure carbon atoms. These thermal treatments generally include a carbonizing process and a graphitizing process. The carbonizing process consists in pyrolyzing non-carbon elements at a temperature between 800 CC and 1300° C. The graphitizing process applies heat at a higher temperature between 2300° C. and 3000° C. so that the carbon atoms are displaced and rearranged so as to form a layer having continuous and ordered arrangement of carbon atoms. The obtained graphite film is then subjected to a rolling treatment to form a flexible graphite film, which can be used as a heat dissipation layer or electromagnetic wave shielding layer in an electronic device.
Some existing approaches propose to use polyimide films of a given thickness for fabricating graphite films of different thicknesses. The implementation of these approaches requires changing the temperature and time of the graphitizing process so as to control the thickness of the formed graphite film. However, this method requires high process controllability, which may be difficult to achieve in practice.
Therefore, there is a need for a process of fabricating a graphite film that can be more easily implemented, and overcome at least the aforementioned issues.